Electrocardiography and Prognosis

Electrocardiography has been accorded distinction as a valuable diagnostic adjunct, but as yet relatively little attention has been given to its prognostic value.I have been especially interested in the study of abnormal electrocardiograms with special reference to clinical types of heart disease and the significance of these graphic changes with regard to life expectancy.In the analysis of large groups of cases of heart disease one is impressed with the frequent occurrence of certain graphic abnormalities in definite clinical types of cardiopathies.Such cases invariably present unmistakable objective evidence of high grade myocardial disease.I am referring particularly to significant T wave negativity, to aberration of the QRS complex in all deriva- tions of the electrocardiogram, and to the coexistence of these abnor- malities.From the standpoint of prognosis, these changes constitute three well defined groups.A very obvious fact that is brought to the attention of those who correlate large clinical and electrocardiographic data is the inability to foretell the presence or absence of these graphic changes in similarly damaged hearts.Electrocardiography was introduced in the Mayo Clinic in 1914 and careful detailed records have been maintained of all patients examined electrocardiographically.The cases are grouped and sub- grouped according to clinical and electrocardiographic types, and an automatic follow-up system of patients has been established.It is thus possible to obtain accurate mortality statistics and definitely to establish the length of life from the time of, examination, and in some instances, from the onset of cardiac symptoms.In a previous article 1 I discussed wave negativity, its occurrence in certain isolated and combined derivations of the electrocardiogram, its occurrence in clinical types of heart disease, and the prognostic significance of certain graphic arrangements.All cases were included regardless of the association of other graphic abnormalities, particularly aberration of the QRS complex affecting all derivations.